You work as a network engineer at domain .com. Study the topology exhibit carefully. In a reorganization, OSPF areas are realigned. Is this a valid network design? If not, which changes could be made to the network and/or router configurations? (multiple answer)
Exhibit:

A.
No changes are necessary.

B.
A virtual link could be configured between Area 60 and Area 0.

C.
A serial line or other physical connection could be installed between devices in Area 60 and Area 0.

D.
Router B could be configured as an Area Border Router between Area 60 and Area 6.

E.
This is not a valid design, and no changes can make it work.